Ultra high frequency antenna



Dec. 16, 1941. L. G. ZUKER'MAN ULTRA HIGH FREQUENCY ANTENN A Filed Feb. 25, 1941 F/G-lfl INVENTOR Patented Dec. 16, 1941 ULTRA men FRE U NeYANTENuA Lester G. Zukerman, Hollywood, Cali.f., assignor to Lockheed Aircraft Corporation, Burbank,

Calif.

Application February 2 and/or antenna mast, especially An external radio antenna, whether of the vertical radiator, or horizontal wire type, requires an electrical lead-in passage which insulates the antenna and'its associated transmission line from the hull or fuselage. The present invention relates to such a dual purpose insulating passage, and provides an structural mounting for the antenna that is readily removable and to which various types of antenna can be applied which may be of such lengths as to tune to the desired ultra high frequencies. The mounting of'this invention pro vides smoothly faired contours from the streamlined'mast to the skin of the fuselage, thus making for low turbulence and low aerodynamic drag, as well as absence of external crevices and the like that would facilitate the collection of dirt which would tend to bridge the dielectric and therebyreduce the resistance of the leakage path.

It is accordingly an object of this invention to provide an improved and simplified means of mounting an end-fed ultra high frequency antenna on an all metal aircraft. The antenna is formed as a streamlined shell of sheet metal, and may be fed by-the inner conductor of a coaxial feeder cable connected thereto through the hollow centenof an insulating mounting block. The outer conductor of the coaxial feeder cable connected thereto through the hollow center of. an insulated mounting block. The outer conductor of the coaxial cable terminates at the mounting block, which insulates it from the antenna, so that it can be at ground potential, or above, as desired. The use of a coaxial cable so I connected to the insulted mast renders the connection impervious to dirt or foreign matter which might otherwise affect the electrical characteristics of the coupling. It is a further object of this invention to provide an improved and simplified dielectric moimting block and/or mast for a fixed antenna,

' which block isreadily applied to and removed from the shell or skin of an airplane and which is adapted to receive interchangeable streamlined antenna. shells tuned to different frequences, which shells are also adapted to support conventional wire antennae if so desired.

Other and further objects of this invention improved insulating compression molding process a the accompanying 5, 1941, Serial No. 380,516 5 Claims. (01.25043) will become apparent as the description of the invention proceeds.

. This'invention, in a preferred form is shown in drawing, wherein:

Figure I is a fragmentary side view of the nose of an airplane fuselage in which an antenna embodying the features of this invention has been installed.

Figure II is an enlarged inside view of the base of the mast, as mounted in the fuselage, the view being indicated by the section line ure I.

Figure III is a longitudinal section of the antenna, on the line III-J11 of Figure II.

Figure IV is a fragmentary section through the supporting block, on .the line IV-IV of Figure III. v

As-shown on the drawing:

It' will be appreciated that while the antenna of this invention is shown as depending from the lower surface of an airplane fuselage orcabin l0, it is equally adaptable for top or other mountings.

' The usual structure of an all metal fuselage comprises a skin ll supported by transverse bulkhead rings l2, and. longitudinals l3, one panel thereof being shown in an inner skin panel 14 is arranged to bridge the panel space between adjacent bulkhead rings to provide for clamping the base l5 of an antenna block [6 against the outer skin II.

The antenna block 16 is preferably formed by a from a plastic having good dielectric, and the necessary physical and chemical properties. Polymerized styrene is an example of a suitable material having extremely low loss electrical characteristics. While I the block, as disclosed herein, can be conveniently molded as a single piece, it'is possible to make it as two or more pieces subsequently Joined by cementing together. The mast-l6 is formed as a streamlined cylinder having a central cored hole H, the cylinder conforming to the inside dimensions ofan antenna shell [8 of streamlined form, the open end of which slips over the mast and is retained in place we series of countersunk 'screws l9 engaging a gang of elastic stop nuts 20 in the centralhole II. The

- antenna shell [8 is preferably dimpled for the heads of the screws l9, and grooves are formed in the sides of the mast l6 to permit assembly and removal of the dimpled shell l8.

. It will be noted that the dielectric mast l6 and the corresponding part of the antenna shell ll are of substantially parallel streamlined cylinder 11-11 in Fig- Figure, II, wherein tapers to a narrow end while maintaining its streamline form. If the mast and shell are to' be used to support a wire typeof antenna 22, a plate 23 is welded into the shell near its outer end, and a connecting link 24 is bolted thereto to support suitable antenna wires 25. The wire antenna may use the shell l8 as a lead in, or a separate lead-in wire 26 may be used as shown if the antenna shell circuit.

The shell I8 is electrically connected to a cen- I8 is to be used in a separate tral pin 21 in 'a detachableplug receptacle 28- by means of an extension piece 29 carrying a nut engaged by the innermost screw 30 shown in Figure IV. The receptacle 28 is mounted in an enlargement of'the central hole in the mast l6, being exposed on the inner surface of the base 15. With this arrangement the electrical connection can be broken at the receptacle 28 and the various screws l9 and 30 removed to remove the antenna shell l8, which shell can be replaced with another, tuned to a different wave length. The base and mast can also be removed from the skin of the fuselage and replaced by a closure using the same screw holes: that mounted the i base I5.

Inasmuch as the cylindrical portion of the mast l6 acts as a cantilever beam, material may conveniently be removed from the trailing edge as at 3|, without affecting the strength, as a full bearing surface would still remain ahead of the major diameter normal to the streamline axis.

It will be noted that the assembly, installation, and servicing of this unit and its electrical connections is especially convenient. It is desirable, but not necessary to add reinforcement 32 to the inside of the skin H, about the aperture therein through which the mast projects, and to provide a rubber-like gasket 33 between the skin and the base l of the dielectric. The completely assembled mast may be inserted into position from the inside of the fuselage and bolted in place by screws and nuts 34 extending through the skin, gasket, base I5, and inner skin M, to clamp the assembly together; the inner skin being addition-' ally secured to the bulkhead rings l2.

It will thus be seen that I have invented an improved and simplified ultra high frequency antenna, which can also be used as a mast supporting wire antennae for other frequencies.

Having thus described my invention and the.

present preferred'embodiment thereof, I desire to emphasize the fact that many modifications may be resorted to in a manner limited onlyby a just interpretation of the following claims.

I claim: 1.'An antenna mast construction, comprising a streamlined radiator shell of the desired ultra high frequency characteristics, and supporting construction, While the balance Of the and means therefor. comprising a di- I electric member having an outstanding projection adapted to telescope into said radiator shell and a base adapted to be secured to a supportin surface in faired relationship to the radiator supporting projection, and means providing a detachable electrical connection from said radiatorv shell to the interior surface of said dielectric base.

2. An antenna mast construction comprising a base member of dielectric material adapted to be fillsh mounted relative to its vehicle, a streamlined cylinder of said material projecting outwardly from the base member and having a passage therethrough, gang nuts arranged in said passage, an ultra high frequency antenna comprising a shell adapted to be engaged over said streamlined cylinder and removably secured to said gang nuts through the material of said memher, and a lead-in connection extending through tionship to said skin, side channels formed in said mast-to receive dimples formed in the shell, countersunk fastening means extending from said dimples to the passage in said base and mast, and a lead-in connection extending through said passaged base into electrical connection with one of said fastening means.

4. An ultra high frequency radio radiator comprising a streamlined shell, and mounting means for removably supporting said shell ininsulated relationship to the skin of an all metal airplane, comprising a passaged base of dielectric material removably secured to said skin and having an outwardly projecting mast removably enveloped by said radiator shell whereby to support the same in insulated relationship to said skin, fastening means extending. from the shell to the passage in said mast. and a lead-in connection extending through said passaged base into detachable electrical connection with said fastening means.

5. An airplane radio antenna radiator comprising a streamlined'shell, and supporting means therefor comprising a dielectric having a base secured to the skin of said airplane and a streamlined projection fitting into the base of said shell, said dielectric being apertured for removable fastening means extending transversely from said. shell, and a lead-in-wire connection insulated from the skin 01 the airplane.

' LESTER G. ZUKERMAN. 

